Proponents argue that natural gas has far fewer negative environmental impacts when compared to the use of other fossil fuels and claim, therefore, that this makes it a ‘safer’ option. However, the reality of using natural gas is somewhat different.
Whilst it’s true that natural gas is typically less harmful than either coal or oil, this doesn’t negate the impact it does have. As awareness of climate change grows, the environmental impact of using natural gas must be objectively assessed, both in terms of using the gas itself and the process of extracting and refining it.
Natural Gas Emissions
The U.S. National Energy Technology Laboratory (NETL) estimates that natural gas produces 50-60 percent less carbon dioxide (CO2) and 20-30 percent less than oil when burned. However, these estimates are based on combustion taking place in new, efficient facilities. As many power plants have yet to embrace more environmentally friendly processes and equipment, the comparable impact might not be quite so varied.
It is generally accepted, however, that burning natural gas is less harmful than using either coal or oil. In terms of tailpipe emissions from vehicles, for example, the U.S. Department of Energy maintains that natural gas releases 15-20 percent fewer heat-trapping gases when compared to gasoline.
At first glance, it seems that natural gas is the least harmful fossil fuel in terms of environmental impact. However, more detailed analysis reveals the net environmental impact of natural gas is far greater than may be anticipated.
Natural Gas and Methane Leakage
When extracted and transported via pipelines, natural gas can leak a substantial amount of methane. As methane is significantly stronger than carbon dioxide in terms of trapping heat, the release of this gas vastly increases the negative environmental impact of natural gas. Indeed, some claim that methane leakage accounts for one to nine percent of natural gas life cycle emissions.
Whilst the environmental damage arising from carbon dioxide emissions may be lesser from natural gas than other fossil fuels, the relatively high methane output could render it either equally as harmful or more harmful than the use of coal or oil.
Air Pollution and Natural Gas
Although natural gas produces nitrogen oxides (NOx) when it’s burned, the amount produced is less than other fossil fuels. Similarly, natural gas only produces a negligible amount of mercury, sulfur, and particulates when it’s burned.
These benefits are tempered, however, by the air pollution which affects local air quality in areas in which unconventional gas developments are situated. In regions surrounding well sites, for example, air contaminants are higher, thus harming both the environment and posing health risks, as highlighted by the Environmental Protection Agency.
Natural Gas Extraction
To access gas in its natural form, drilling is typically used. As well as considering the environmental impact of this methodology in terms of air pollution, the impact that drilling has on ground level cannot be ignored.
Whilst vertical drilling is the most common form of extraction, it causes environmental damage by definition. As well as the erosion of minerals and pollutants into nearby water sources, the act of drilling into the earth poses a significant risk. As vertical drills are used to access reservoirs of natural gas, they affect the layers of sediment and rock which form the underground structure upon which we rely.
Furthermore, the increasing use of directional and horizontal drilling methods has led to increased environmental impacts. Horizontal fracturing, in particular, has been associated with triggering earthquakes. In addition, horizontal fracturing, or fracking, is known to release additional amounts of methane into the atmosphere during the extraction process and requires a significant number of chemicals in order to access natural gas. Another harmful environmental impact of this type of extraction process is the toxicity of water which is returned to the ground following fracking. As well as using up large reserves of water, it’s estimated that at least 20-40 percent of the returned water contains contaminants which are harmful to the environment and pose further health risks.
Industrial Use of Natural Gas
The World Watch Report 184 maintained that natural gas combined cycle power plants produce around 50 percent less CO2 than modern coal plants. By switching to gas-powered applications and gas-fired electric generation, it is possible that the overall environmental impact of industries would be lessened. Indeed, using gas in addition to other fossil fuels could significantly reduce the harmful emissions produced.
The increasing use of combined cycle generation also favors the use of natural gas, as gas-fired combined-cycle generation units may be up to 60 percent more efficient than standard generation. In comparison, oil and coal generation units are estimated to be around 30-35 percent more efficient than standard generation.
As a result, utilizing natural gas industrially could reduce the current negative environmental impact, improve air quality, and produce fewer emissions.
Environmental Impact of Natural Gas
Whilst natural gas is generally considered to be more environmentally friendly than other fossil fuels, this should not overshadow the environmental impact it does have. Although some engineering firms are using technology to minimize the environmental impact associated with the natural gas, others are relying on controversial methods of extraction that could increase the damage the use of natural gas causes.
Currently, the true impact of natural gas depends on the way it’s extracted and refined, as well as the way it is ultimately used. In addition, the supply logistics play a significant role in how much methane is leaked and, therefore, have an impact on the overall environmental effects of natural gas.
With a worldwide commitment to more sustainable extraction methods, the existing environmental impact of natural gas could be reduced. Without this commitment, however, the cost benefits associated with newer forms of extraction could see the harmful environmental impact of natural gas increase.
Whilst the environmental fallout associated with natural gas is often cited favorably in comparison to the impact of other fossil fuels, this does not equate to a positive or neutral impact. Although natural gas may not have quite the same level of environmental impact as other fossil fuels, it undoubtedly contributes to reduced air quality and increased greenhouse gases and, therefore, has an undeniable impact on the environment.